Canonical URL availability

[zeepartner]

Hi

We have a website selling cellphones. They are available in different colors and with various data capacity, which slightly changes the URL.

For instance:

• Black iphone, 16GB: www.site.com/iphone(black,16,000000000010204783).html
• White iphone, 16GB: www.site.com/iphone(white,16,000000000010204783).html
• White iphone, 24GB: www.site.com/iphone(white,24,000000000010204783).html

Now, the canonical URL indicates a standard URL:

But this URL is never physically available. Instead, a user gets 301 redirected to one of the above URLs. Is this a problem? Does a URL have to be "physically" available if it is indicated as canonical?

[zeepartner]

Thanks Dirk for your great in-depth response!

I will now check with developers what the estimated effort would be. Making the canonical URL available will let me sleep better at night before releasing the new site version.
I think the risk shouldn't be huge if we cannot do this and will not waste too many ressources on this (unless, of course, we see a negative impact, which I will then report here;)

Best, 
Phil

[DirkC]

With a 301 you communicate that the requested resource is no longer available (The requested resource has been assigned a new permanent URI and any future references to this resource SHOULD use one of the returned URIs- source: http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html)

If you look at the definition of a canonical url - it indicates the preferred URL to use, so that the search results will be more likely to show users that URL structure. (Google attempts to respect this, but cannot guarantee this in all cases.)

So basically what you are telling to Google:

On your site you ask Google not to index site.com/A.htm - but rather to index url site.com/B.htm
On the url site.com/B.htm you put a 301 to site.com/C.htm - in other words force Google to index C.htm rather than B.htm (the 301 indicates that the page has permanently moved to a new location - so is no longer available on B.htm)

So in fact - you ask Google not to index A.htm but C.htm instead. Rather than doing this in a complicated 2step process using both canonical & redirect it would be simpler & make more sense to directly put a canonical url on A.htm with C.htm as canonical.

In your case you could create www.site.com/iphone but if it's identical to www.site.com/iphone(black,16,000000000010204783).html I don't think you will gain a lot (especially if it requires a lot of development)

rgds,

Dirk

[zeepartner]

Thank you Dirk!
I did look at the article you pointed out, but could not initially find that information:
"Double-check that your rel=canonical target exists (it’s not an error or “soft 404”)"

However, for me this is not 100% conclusive. The page does exist, in a way, but it's redirected. I know that to be on the safe side, we should better make it available. But as it would mean a lot of additional programming effort, I am trying to find out if it really is necessary. Thats' why I was hoping someone already has some experience with this...

[DirkC]

Normally a canonical url should be physically available - see also: http://googlewebmastercentral.blogspot.be/2013/04/5-common-mistakes-with-relcanonical.html

With a canonical you indicate the Search engines which page you want to have listed in the SERP's. A page which is 301'd to another page will never get listed in the results.

In your case - it's probably better to use the url where your are redirecting to as canonical - or to create a page www.site.com/iphone that is not redirected

rgds,

Dirk